Absorbable surgical coil fastener

ABSTRACT

A surgical fastener deployment system may include a plurality of coil fasteners having a head and coil body. In some embodiments, the head is comprised of a bioabsorbable polymer. In one embodiment, the coil body may be comprised of a shell and a core and one of the shell and the core may be comprised of one of a magnesium alloy or a bioabsorbable polymer, and the other of the shell and core is formed of the other of the magnesium alloy and the bioabsorbable polymer. The coil body may also include an internal channel which may have a support coil disposed within.

FIELD

Embodiments disclosed herein are related to surgical fasteners, and moreparticularly, to absorbable surgical coil fasteners.

BACKGROUND

Surgical fasteners are widely used in many different medical procedures.For example, staples, sutures, clips, tacks, coil fasteners and otherfastener types are commonly used in laparoscopic and open surgicalprocedures.

SUMMARY

The embodiments disclosed herein describe a surgical fastener. In someembodiments, the surgical fastener is composed of a head, and a coilbody that extends distally from the head. The coil body could include ashell that at least partially surrounds a core, and the shell is made ofa magnesium alloy or a bioabosrbable polymer, while the core could bemade of whichever of the magnesium alloy or the bioabsorbable polymerthat the shell is not made of. The surgical fastener could have atransverse dimension of between or equal to 0.018 to 0.035 inches. Themagnesium alloy could have a yield strength of between 314 MPa to 506MPa, and the shell could have a thickness between 0.010 to 0.20 inches.

In other embodiments, the surgical fastener is composed of a head, and acoil body extending from the head, and the coil body includes a channelthat extends along at least a portion of the length of the coil body.The surgical fastener could have an opening on the proximal surface ofits head, wherein the channel of the coil body may be accessible throughthe opening. Some embodiments have the channel extending along theinterior of the coil body, while others have it external to the coilbody. The channel could be constructed and arranged to receive a supportsuch that the support is partially disposed within the channel as thesurgical fastener is deployed from a deployment device.

Also disclosed is a method of applying a surgical fastener involvinginserting a support into a channel formed in and extending along atleast a portion of a length of a coil body of a fastener, and deployingthe surgical fastener while the support is at least partially located inthe channel. In some embodiments of the method, the supported isinserted into the channel through a hole formed in a head of the coilfastener, and the fastener may be rotated as it is deployed. In channelmay extend along the entire length of the coil body, and the supportcould be removed from the channel when the surgical fastener is deployedor after the surgical fastener is deployed.

In other embodiments, the surgical fastener is composed of a head and acoil body extending distally from the head, where the coil body iscomposed of a magnesium alloy with a yield strength of between or equalto 314 MPa and 506 MPa, and has a transverse dimension of between orequal to 0.018-0.035 inches. The magnesium alloy could be comprised ofat least magnesium, dysprosium, neodymium and/or europium, and zincand/or zirconium. The head of the surgical fastener could bebioabsorbable. The surgical fastener could be used in conjunction with asurgical fastener deployment system for deployment.

In other embodiments of a surgical fastener, the surgical fastener ismade of a head and a coil body which extends distally from the head. Thecoil body in these embodiments is composed of a magnesium alloy that is5.0%-25.5% by weight dysprosium, 0.01%-5% by weight neodymium and/oreuropium, 0.1%-3.0% by weight zinc, and 0.1%-2.0% by weight zirconium.The head may be made of a bioabsorbable material. And the coil body mayhave windings with transverse dimensions between 0.018 inches and 0.035inches. The surgical fastener could also be used in conjunction with asurgical fastener deployment device for deployment.

It should be understood that the foregoing concepts, and additionalconcepts discussed below, are described herein with reference to certainillustrative embodiments and the figures. The illustrative embodimentsdescribed herein are not necessarily intended to show all aspects, butrather are used to describe a few illustrative embodiments. Thus,aspects are not intended to be construed narrowly in view of theillustrative embodiments. In addition, it should be understood thatcertain features disclosed herein might be used alone or in any suitablecombination with other features.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures may be represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a schematic perspective view of an embodiment of a surgicalfastener including threading on a through hole formed in a head of thefastener;

FIG. 2 is a schematic side view of the surgical fastener of FIG. 1;

FIG. 3 is a schematic side view of an embodiment of a surgical fastenerincluding a thread on an external surface of a head of the fastener;

FIG. 4 is a cross-sectional view of one embodiment of a surgicalfastener including a solid coil body;

FIG. 5 is a cross-sectional view of one embodiment of a surgicalfastener including a composite coil body including a core and shellcomprised of different materials;

FIG. 6 is a cross-sectional view of one embodiment of a coil body with ashell overmolded around a core of the coil body;

FIG. 7 is a cross-sectional view of one embodiment of a coil body with ashell that partially encompasses a core of the coil body;

FIG. 8 is a cross-sectional view of one embodiment of a coil body with ashell deformed around a core of the coil body;

FIG. 9a is a cross-sectional view of one embodiment of a surgicalfastener where a coil body is internally supported by a selectivelyinsertable support core, prior to the insertion of the support core;

FIG. 9b is a cross-sectional view of the surgical fastener of FIG. 7aafter insertion of the support core into the coil body;

FIG. 10a is a cross-sectional view of one embodiment of a coil bodywinding including a hollow internal channel;

FIG. 10b is a cross-sectional view of the coil body winding of FIG. 10awith a support core inserted into the channel;

FIG. 11a is a cross-sectional view of one embodiment of a coil bodywinding including an open channel extending along a length of the coilbody;

FIG. 11b is a cross-sectional view of the coil body winding of FIG. 11awith a support core inserted into the open channel;

FIG. 12 is a schematic side view of an exemplary deployment device thatcould be used to deploy the disclosed surgical fasteners; and

FIGS. 13a-13c are cross-sectional views of a deployment device loadedwith a surgical fastener during deployment.

DETAILED DESCRIPTION

The Inventors have recognized that magnesium alloys offer desirablecharacteristics for inclusion in a surgical fastener such as, forexample, the ability to be sharpened and maintain a point as well as thebiocompatibility and bioabsorption characteristics of magnesium alloys.However, prior magnesium alloys exhibited relatively low yield andtensile strengths which limited their use in surgical fasteners.

In view of the above, the Inventors have recognized the benefitsassociated with forming surgical fasteners with recently developedhigher strength magnesium alloys and/or with composite structures toenable the formation and use of various types of coil fasteners.

In one embodiment, a surgical fastener includes a coil body composed ofa magnesium alloy. In some applications, a yield strength of themagnesium alloy and a maximum transverse dimension, e.g. diameter, of across section of a coil winding of the coil body may be selected suchthat the coil body does not exhibit significant amounts of plastic (i.e.irreversible) deformation when deployed. Appropriate dimensions andmaterials properties of the coil body are described in further detailbelow.

In embodiments where a solid coil body is used in a surgical fastener,the coil winding of a coil body may have a cross section with an outertransverse dimension, e.g. diameter, that is between or equal to 0.46 mmto 0.89 mm (0.018-0.035 inches), 0.5 mm to 0.79 mm (0.020-0.031 inches),or 0.56 mm to 0.69 mm (0.022-0.027 inches). Additionally, the coil bodymay be made from a biocompatible and/or bioabsorbable magnesium alloywith a yield strength between or equal to 69 MPa to 506 MPa (10-73 ksi)or 206 MPa to 506 MPa (30-73 ksi) or 314 MPa to 506 MPa (45.5-73 ksi).In some embodiments, the magnesium alloy may also have a compositionthat is 5.0%-25.5% by weight dysprosium, 0.01%-5% by weight neodymiumand/or europium, 0.1%-3.0% by weight zinc, 0.1%-2.0% by weightzirconium, 1 ppm-0.4% by weight impurities, and a balance to 100.0% byweight magnesium. However, other biocompatible and/or bioabsorbablemagnesium alloys exhibiting sufficient yield strengths may also be usedas well.

In another embodiment, a surgical fastener includes a composite coilbody. Specifically, the composite coil body may include a coil windingthat comprises a core made from a first material and a shell at leastpartially surrounding, and in some instances completely surrounding, anexterior perimeter of a cross section of the core made from a seconddifferent material. The shell may be disposed on the core either alongan entire length of the coil body or only along a portion of the lengthof the coil body.

In instances where a shell of a coil winding does not completely coverthe perimeter of a corresponding cross section of a core of the coilbody, the shell may be positioned on any appropriate face of the coilbody. For example, in one embodiment, a shell may be located on aninterior side of the coil body that faces an interior of the coil body(i.e. directed toward an interior of the surgical fastener) or on anexterior side of the coil body directed outward from the surgicalfastener. Thus, it should be understood that the particular orientationand arrangement of a shell on a core is not limited to only thosespecific embodiments described herein.

As noted above, the shell and core of a coil body may be comprised ofdifferent materials. For example, in one embodiment, the shell is eithera magnesium alloy or bioabsorbable polymer and the core is the other ofthe magnesium alloy and bioabsorbable polymer. Therefore, in onespecific embodiment, the shell is comprised of a magnesium alloy, whilethe core is comprised of a bioabsorbable polymer. In another specificembodiment, the shell is comprised of a bioabsorbable polymer, while thecore is comprised of a magnesium alloy. However, while a magnesium alloyis specifically mentioned above, it should be understood that othertypes of materials including different polymers, different metallicmaterials, and/or any other appropriate materials may be used to formthe disclosed composite coil bodies as the disclosure is not so limited.

In embodiments where a coil body of a surgical fastener comprises a coreand shell, an outer transverse dimension, e.g. a thickness or adiameter, of a cross section of a coil winding of the coil body, whichmay be viewed as a transverse dimension of the combination of the coreand shell, may be between or equal to 0.46 mm to 0.89 mm (0.018-0.035inches), 0.5 mm to 0.79 mm (0.020-0.031 inches), or 0.56 mm to 0.69 mm(0.022-0.027 inches), though thicker and thinner coil bodies are alsocontemplated. The shell may have a thickness between or equal to 0.127mm to 0.3 mm (0.005 and 0.012 inches), 0.15 mm to 0.20 mm (0.006 and0.008 inches), or any other appropriate thickness. Correspondingly, thecore may have a transverse dimension, such as a thickness or diameter,of a cross section of the core that is between or equal to 0.25 mm to0.51 mm (0.01 inches and 0.02 inches), 0.25 mm to 0.64 mm (0.01 inchesand 0.025 inches), or any other appropriate dimension includingdimensions both greater and less than those noted above.

Composite coil bodies comprising a core and a shell may be manufacturedin any suitable way. For example, in some embodiments, a coil body coreis dipped into a liquid or molten material that may either solidify,harden, or cure to form a shell on the core. The shell material may alsobe overmolded onto a core of a coil body. In another embodiment, a shellis wrapped, or otherwise deformed, partially or fully around apre-formed core to produce a final composite coil body. In such anembodiment, the composite may then be deformed into the desired shape ofthe coil body. In yet another embodiment where the outer shell is amagnesium alloy, or other metallic or hard material, a molten or uncuredcore material may be injected into an internal channel formed within ashell. The core material may then harden or cure within the channel toform the core of a composite coil body. Several of these methods areelaborated on in further detail below in regards to the figures. Ofcourse, while specific methods and constructions have been discussed,other suitable methods of manufacturing the core and shell are alsocontemplated as the current disclosure is not so limited.

In some applications it may be desirable to provide a surgical fastenerwith a hollow coil body with a channel that extends along at least aportion of a length of the coil body. However, such a structure may notexhibit sufficient strength to be deployed without buckling or otherwisedeforming. Accordingly, in some embodiments, it may be desirable tosupport at least a portion of the surgical coil fastener as it is beingdeployed. In one such embodiment, a surgical fastener includes a coilbody with a shell or outer tube that forms a channel extending along atleast a portion of a length of the coil body. In such an embodiment, atleast a portion of the coil body's length may be supported by a support,such as a supporting coil or core during deployment of the surgicalfastener. The support may be sized and shaped to selectively fit withinthe channel of the coil body to support, i.e. resist deformation of, thecoil body during at least a portion of a deployment phase of theassociated surgical fastener. The supporting coil and channel may extendthrough either the entire length of the coil body (i.e. form a proximalend of the coil body to a distal tip), or only through a portion of thecoil body as the disclosure is not so limited. The supporting structuremay be inserted into the channel when supplied to a user, during, orprior to deployment of the fastener, or in any other appropriate manner.The supporting coil may then be retained within the channel of the coilbody during at least a portion of deployment of the fastener to providethe desired support to the coil body of the fastener as it is deployedinto tissue, bone, and/or prosthetic devices.

In some embodiments where a support is used with a coil body, the coilbody may be comprised of a magnesium alloy, but other biocompatiblematerials sufficiently stiff for use in surgical fastening applicationsare also contemplated. Further, a support, such as a supporting coil,may be made from 316 LVM stainless steel which has an ultimate tensilestrength of 1503 MPa to 1641 MPa (218-238 ksi) and a yield strength of1317 MPa to 1641 MPa (191-238 ksi) at 2.6% elongation. Other possiblematerials include other stainless steels, nitinol, and titanium alloys,though the current disclosure is not limited to just these materials.Further, it is contemplated that a support may be made of any othersuitably stiff material capable of sufficiently supporting the coil bodythrough a combination of a larger elastic modulus and/or thickness.Thus, through the use of these design parameters, the support may bestiffer than the coil body.

In embodiments where a support is used, a transverse dimension, such asa thickness or diameter, of a cross section of a coil winding of a coilbody may be between or equal to 0.46 mm to 0.89 mm (0.018-0.035 inches),0.5 mm to 0.79 mm (0.020-0.031 inches), or 0.56 mm to 0.69 mm(0.022-0.027 inches). Correspondingly, a channel formed in the coilwindings may have a transverse dimension, such as a width or diameter ofthe channel, that is between or equal to 0.13 mm to 0.64 mm (0.005 to0.025 inches), 0.25 mm to 0.51 mm (0.010 to 0.020 inches), or any otherappropriate dimension. The support may be correspondingly sized andshaped to be insertable and removeable from the channel within the coilbody. However, while specific dimensions for the coil windings, supportand channels are described above, different dimensions both larger andless than those noted above are contemplated as well.

In some embodiments, the above noted surgical fasteners including coilbodies may be attached to a corresponding head. In such a configuration,the coil bodies may be attached to and extend distally from the heads.The head may also be configured to have a transverse dimension that islarger (wider and/or greater in diameter), than an outer transversedimension of the coil body to engage and secure underlying materialand/or tissue. In addition to helping with fixation of tissue andprosthetics, the head of a surgical fastener may include one or morefeatures that cooperate with corresponding features of a delivery devicefor driving the fastener from the device and into an implantableprosthesis and/or tissue, bone, or muscle. For example, a head may havea through hole including one or more threads formed within the throughhole that interact with a threaded mandrel to deploy the fastener.Alternatively, in another embodiment one or more threads may be formedon an exterior perimeter of the head to interact with a threaded tubethat the surgical fastener is positioned in to deploy the fastener.

A head may be attached to a surgical fastener in any number of ways. Forexample, depending on the embodiment, the head may include an internalthread that is threaded to the coil body and attaches the head to aproximal end of the coil body. In another embodiment, the head may besecured to the coil body with a compression or press fit between thehead and a proximal portion of the coil body. The head may include acavity, such as a counterbore or a through hole, that receives theportion of the coil body therein to provide the compression or pressfit. More specifically, the portion of the coil body received in thecavity may have an outer transverse dimension in a relaxed state that islarger than, or equal to, a transverse dimension of the cavity to createthe compression or press fit as the coil body is threaded to the head.The portion of the coil body received in the cavity may includeapproximately a half turn or more of at least one coil, or other featureassociated with the coil body. In yet another embodiment, a coil bodymay be attached to a head by overmolding the head onto a proximalportion of the coil body. While certain constructions are noted above,it should be understood that the various attachment methods may becombined with one another and other types of attachment methods may beused as the disclosure is not so limited.

Depending on the embodiment, a distal end of a coil body may beconfigured to penetrate an implantable prosthesis, bone, muscle and/ortissue. In such an embodiment, the distal tip of the coil body could besharpened or blunt depending on the characteristics of the targettissue. The distal end of the coil body could also be comprised of adifferent material than the rest of the coil body. The distal end may becomprised of a biocompatible material such as stainless steel, nitinol,titanium or any other sufficiently stiff to penetrate tissue, but alsomalleable enough to be easy to blunt or sharpen when compared to therest of the coil body.

Appropriate bioabsorbable polymers that may be used with the above notedembodiments, include, but are not limited to, a poly(lactic-co-glycolicacid) (PLGA), a poly(lactide-co-glycolide)s (PLG, such as Purasorb PLG8218), a poly(lactic acid) (PLLA), or any other suitable biocompatibleand/or bioabsorbable polymer.

Again, it should be understood that any appropriate magnesium alloy, orother appropriate biocompatible and/or bioabsorbable metal or metalalloy, may be used with the above embodiments. However, in oneembodiment, a shell, core, or other component of a coil body may be madefrom a biocompatible and/or bioabsorbable magnesium alloy with a yieldstrength between or equal to 69 MPa to 506 MPa (10-73 ksi), 206 MPa to506 MPa (30-73 ksi) or 314 MPa to 506 MPa (45.5-73 ksi). One suchexemplary magnesium alloy includes Resoloy manufactured by MeKo whichmay have a composition that is 5.0%-25.5% by weight dysprosium, 0.01%-5%by weight neodymium and/or europium, 0.1%-3.0% by weight zinc, 0.1%-2.0%by weight zirconium, 1 ppm-0.4% by weight impurities, and a balance to100.0% by weight magnesium. This particular alloy may have an ultimatetensile strength of 461 MPa (66.8 ksi), and a yield strength of 403 MPa(58.5 ksi) at 2.6% elongation. However, other biocompatible magnesiumalloys of sufficient strength for surgical applications are contemplatedas well.

In addition to the above, in some embodiments, the materials used toform a head and coil body of a surgical fastener are capable of eitherbeing sterilized before, during, or after assembly and packaging tomaintain sterility, and/or is sterilizable for use.

In the above noted embodiments, a length of a coil body extendingdistally from a distal face of an associated head may be between orequal to approximately 3 mm to 6.5 mm, 4 mm to 5.5 mm, or 4.5 mm to 5mm. The coil body may also include approximately 2.5 turns toapproximately 6 turns of coil windings. An outer transverse dimension ofthe coil body may be between or equal to approximately 2.5 mm toapproximately 4.9 mm (0.098 inches to 0.193 inches). Thus, the coil bodymay be sized and shaped to facilitate deployment of the surgicalfasteners through a 5 mm cannula. A pitch of the coil windings of thecoil body may also be between or equal to approximately 0.7 mm toapproximately 1.1 mm (0.03 to 0.045 inches). However, other coil bodylengths, head lengths, outer transverse dimensions and pitches greaterthan or less than the previously stated values are also contemplated asthe current disclosure is not limited to the above values.

In some embodiments, a head attached to a coil body has an outertransverse dimension that is between or equal to approximately 2.7 mm toapproximately 4.98 mm (0.106 inches to 0.196 inches) or 3.0 mm to 4.6 mm(0.12 inches to 0.18 inches) or 3.5 mm to 4.1 mm (0.14 inches to 0.16inches). A thickness of the head, corresponding to a thickest portion ofthe head in a direction orthogonal to the outer transverse dimension,may also be between or equal to approximately 0.97 mm (0.030 inches) toapproximately 1.02 mm (0.04 inches). Of course, while particulardimensions are given above for a coil body and head, it should beunderstood that a surgical fastener may employ a coil body and headhaving any suitable sizes and configurations for a desired applicationas the disclosure is not so limited.

The above described embodiments of a surgical fastener may be used forvarious surgical fastening applications. For example, the surgicalfastener may be used to attach an implantable prosthesis, such as a softtissue repair fabric, to tissue and/or muscle. Other non-limitingapplications for the fastener may involve joining portions of tissueand/or muscle together, joining portions of tissue and/or muscle tobone, and/or joining an implantable prosthesis to bone and/or tissue. Ofcourse, the currently disclosed surgical fasteners may be employed forother applications as well as the disclosure is not so limited.

Turning now to the figures, several non-limiting embodiments aredescribed in further detail. However, it should be understood that thevarious features and components described in relation to the figures maybe used either individually and/or in any appropriate combination as thedisclosure is not so limited.

In one illustrative embodiment, as shown in FIGS. 1 and 2, a surgicalfastener may include a coil body 102 and a separate head 100 that isattached to a proximal end of the coil body 104. Depending on theembodiment, the distal end of the coil body 106 may be configured forpenetrating an implantable prosthesis, tissue, muscle, and/or bone. Inone embodiment, the distal end 106 may include a sharp distal tip,although the distal end may employ any suitable configuration, includinga blunt distal tip, as the disclosure is not limited in this fashion.

As also depicted in the figures, a coil body 102 may include one or morecoil windings 108 corresponding to one or more full turns of the coilbody extending distally from the head. For example, the depicted coilbody includes coil windings that form approximately four full turnsextending distally form the head. A transverse dimension of a crosssection of a coil winding of the coil body may correspond to a diameteror thickness of the material used to form the coil windings of the coilbody.

As illustrated in the figures, the coil windings 108 may be arranged ina helical or spiral configuration suitable for driving the fastener intoand through prosthetic material, tissue, muscle and/or bone. Thus, insome embodiments a coil body may be cylindrical in shape with a circularcross-section, though non-circular cross-sectional shapes of both thecoil body and/or coil winding such as triangular, square, pentagonal,rectangular, or any other appropriate shape also are contemplated. Thecoil body 102 may include any number of coil windings 108 with anydesired spacing or pitch between the coil windings and any transversedimension, including outer and inner transverse dimensions, suitable fora particular application. In some embodiments an outer transversedimension of the coil body is constant along a length of the coil body.However, if desired, one or more of the coil windings of the coil bodymay have different transverse dimensions relative to each other. Forexample, the coil body may include coil windings that have an outertransverse dimension that decreases in a distal direction to form a coilbody with a conical or tapered shape.

As shown in FIGS. 1-2, to facilitate deployment of the surgicalfastener, in some embodiments, a head 100 of a surgical fastener mayinclude a through hole 114 that passes from a proximal face of the headto an opposing distal face of the head. Additionally, an internal thread116 is formed on an inner surface of the through hole. As describedfurther below, the threaded through hole may be used in conjunction witha threaded mandrel of a deployment device that is received in thethrough hole to deploy the surgical fastener. Alternatively, in anotherembodiment, as depicted in FIG. 3, threads 118 formed on an externalsurface of the head interact with threading on a correspondingdeployment device to deploy the surgical fastener. Of course, whilethreaded fasteners have been depicted above, embodiments, in whichfasteners are deployed using features other than threading are alsocontemplated. For example, a head of the surgical fastener may includeone or more features that mechanically interlock with a deploymentdevice to permit it to be rotated and distally displaced duringdeployment as the disclosure is not limited to any particular deploymentmethod.

FIG. 4 shows a cross-sectional view of one embodiment of a surgicalfastener 200. The surgical fastener includes a head 202 and a solidmagnesium alloy coil body 204. The head is located at a proximal end ofthe fastener and the coil body extends distally from the head. In someembodiments, once deployed into tissue, the head and coil body may beabsorbed by the body.

FIG. 5 shows a cross-sectional view of another embodiment of a surgicalfastener 300. In the depicted embodiment, the surgical fastener includesa head 302 and coil body 304. In this embodiment, the coil body 304 ismade from a composite coil winding including a core 306 and shell 308.The shell at least partially, and in the depicted embodiment completely,encapsulates or surrounds an outer perimeter of the core. The core andshell may be made from different materials as previously discussed. Inone specific embodiment, the core and shell are made from abiocompatible magnesium alloy and a biocompatible polymer, and the headis made from a biocompatible polymer as described above. Additionally,in some embodiments, the shell, the core, and/or head are made frombioabsorbable materials so that they may be absorbed by the body. Ofcourse, other materials for the core, shell, and/or head are alsocontemplated as the current disclosure is not limited to only theaforementioned materials.

FIGS. 6, 7, and 8 show cross-sectional views of different embodiments ofcomposite coil windings 304 including cores 306 and shells 308. Thedepicted composite coil windings include different shapes and may bemanufactured in different ways.

FIG. 6 shows a cross-section of a coil winding 304 of a coil body wherethe shell 308 has been overmolded onto the core 306 to fully encapsulatethe core. Other embodiments of the coil may be formed from spin-coating,or dip-coating, or the shell material being sprayed onto the core. Ofcourse, other suitable methods of producing a shell may also beemployed.

FIG. 7 shows an embodiment of a coil winding 304 of a coil body wherethe core 306 is partially encapsulated by the shell 308. In such anembodiment, the core of the coil body is at least partially exposed to asurrounding environment. In the depicted embodiment, the shell coversthe rounded portion of a semi-circular core. However, other shapes ofthe core such as circular, square, triangular, and rectangular may beused. Additionally, the shell may cover any desired portion of thecore's outer surface as the disclosure is not so limited. Further,despite the non-circular cross-section, the coil body still winds aroundand forms a helical shape with the core partially exposed to theenvironment for at least part of the coil. Additionally, the coil bodymay be arranged such that any portion of the cross section of thedepicted coil winding may be oriented either inwards or outwardsrelative to the coil body as the disclosure is not so limited. Forexample, in one embodiment, the exposed surface of the core may beoriented such that it faces inwards relative to the coil body. However,in another embodiment, the exposed surface of the core may be orientedsuch that it faces outwards relative to the coil body. In the aboveembodiments, the shell may be formed on the core in a number of waysincluding, but not limited to overmolding, lamination, deformation ofthe shell onto the core, or any other appropriate method of attachingthe core to the coil body.

FIG. 8 shows an embodiment of a coil body where a shell 308 has beenapplied by wrapping, rolling, or otherwise deforming a preformed sheetonto a preformed core 306. A seam 310 may be present along a length ofthe coil body in instances where the shell fully surrounds the core.Once the core and shell are assembled the composite structure may bewound into a helical structure to form a coil body.

FIGS. 9a and 9b show a cross-sectional view of one embodiment of asurgical fastener 400 that is supported by a stiffer support, such as asupport coil 408, during deployment. In the depicted embodiment, thesurgical fastener includes a hollow channel 406 that is formed withinthe coil windings 412 and extends along at least a portion of a lengthof the coil body 404. In some embodiments, the channel of the coil bodyextends up to and is accessible through an opening 410 formed in thehead 402. The opening may either be located on a proximal face of thehead and/or a surface of a through hole formed in the head. In eithercase, the channel and opening are shaped and sized such that the supportcoil 408 may be inserted into the opening and channel.

FIG. 9a shows the support coil 408 as it is being inserted into theopening 410 in the head and channel 406 of the coil body. As the supportcoil is rotated relative to the fastener, the support coil is threadedinto the channel of the coil body. FIG. 9b shows the support coil fullythreaded into the channel and coil body. In this embodiment, thesupport, corresponding to the support coil, extends out from a distalend of the coil body. However, embodiments, in which a support andchannel do not extend out from a distal end of a coil body are alsocontemplated.

In reference to the above embodiment, during deployment of a surgicalfastener the support coil 408, or other support, may be disposed in thechannel 406. The surgical fastener, and in some embodiments the supportcoil, are then rotated and advanced distally to deploy the surgicalfastener. Either during, or after the surgical fastener, is deployed,the support coil may be rotated relative to the surgical fastener toremove the support coil from the corresponding channel of the surgicalfastener. For example, the support may extend to a distal tip of anassociated deployment device and held stationary relative to thedeployment device and surgical fastener. Therefore, as the surgicalfastener is rotated relative to the support coil, it is advanceddistally with the support coil located within a portion of the channelstill within the deployment device. Accordingly, the support coil willsupport a portion of the surgical fastener exiting the distal tip of thedevice as it enters into the corresponding tissue, bone, and/orprosthetic. Alternatively, the surgical fastener and support coil may berotated and advanced distally together to support an entire length ofthe coil body as it is deployed into the corresponding tissue, bone,and/or prosthetic. The support coil may then be rotated relative to thesurgical fastener to remove it from the corresponding channel afterdeployment. Of course, it should be understood that other methods andarrangements for deploying a surgical fastener with a support are alsocontemplated as the disclosure is not limited to any particular systemor arrangement.

FIGS. 10a and 10b show a cross-sectional view of a coil winding of acoil body constructed to accommodate a support. FIG. 10a shows the coilbody with a coil winding 404 including an empty inner channel 406. FIG.10b shows the support coil 408 inserted into the channel.

FIGS. 11a and 11b show an embodiment of a coil body including anexternally located channel. In the depicted embodiment a semi-circularcoil winding 412 includes a semi-circular channel 406 formed on anexterior surface of the coil winding. FIG. 11b depicts a support, suchas the support coil 408, inserted into the exterior channel which maystill support the coil body during deployment even though the channeldoes not fully surround the support coil. Of course, differently shapedcoil windings and channels including square, rectangular, pentagonal,and triangular to name a few may also be used. The resulting coilwinding may still be shaped into a helix to form a coil body.Additionally, the channel may be located on an inward facing surface ofthe coil winding directed towards an interior of the coil body or anexterior surface of the coil winding directed outwards from the coilbody interior as the disclosure is not so limited.

The various embodiments of a surgical fastener described herein may bedelivered to a surgical site using a delivery device that impartsrotation to the fastener and drives the fastener into prostheticmaterial, tissue, muscle and/or bone. As shown in FIG. 12, oneembodiment of a delivery device 500 may include a handle 502 including atrigger 504 at a proximal end of the device. The delivery device 500 mayalso include an outer tube or cannula 506 extending in a distaldirection from the handle 502. As shown in FIGS. 13a-13c , in someembodiments, the delivery device may include a mandrel 508 that extendsalong a length of the outer tube or cannula 506 for supporting and/orguiding one or more fasteners 100 within the cannula. The mandrel isconfigured to rotate one or more surgical fasteners 100 positioned onthe mandrel when the mandrel is rotated relative to the outer tube whenthe trigger is actuated. Threaded heads 102 of the fasteners are thenrotated relative to threading 510 formed on an internal surface of theouter tube. Rotation of the fasteners 100 relative to the threaded outertube in turn provides a reactive thrust to the fasteners causing thefasteners to be driven in a distal direction along the length of themandrel 508, out of a distal end of the outer tube 506, and into theprosthetic material and/or tissue.

In embodiments of the surgical fastener that include a channel withinthe coil body and a delivery device including a support, the fastenersmay be pre-loaded into the delivery device with the support alreadydisposed within the channel. In some embodiments, the delivery device isadditionally designed to insert the support into at least a distal mostfastener as it is deployed. The support may then be removed from thecoil body either during or after deployment of the surgical fastener asdescribed previously above.

While a laparoscopic delivery device has been depicted in the abovefigures, the current disclosure is not so limited. Instead, thecurrently disclosed surgical fasteners may be used with any appropriatedevice capable of deploying the disclosed surgical fasteners. Forexample, while a threaded tubular member has been depicted in thefigures, embodiments in which a stationary threaded mandrel androtatable outer tube are used are also contemplated. Additionally, thesurgical fasteners could also be used in other delivery devices such asan endoscopic device, a borescopic device, a catheter, a surgicalinstrument for use in “open” procedures, or any other appropriatesurgical instrument.

It should be understood that the foregoing description of variousaspects of at least one embodiment of the current disclosure areintended merely to be illustrative thereof and that other embodiments,modifications, and equivalents of the invention are within the scope ofthe invention recited in the claims appended hereto. Accordingly, theforegoing description and drawings are by way of example only.

What is claimed is:
 1. A surgical fastener comprising: a head; and acoil body attached to and extending distally from the head, wherein thecoil body includes a shell at least partially surrounding a core,wherein the shell comprises one of a magnesium alloy and a bioabsorbablepolymer and the core comprises the other of the magnesium alloy and thebioabsorbable polymer.
 2. The surgical fastener of claim 1, wherein themagnesium alloy has a yield strength of between or equal to 314 to 506MPa.
 3. The surgical fastener of claim 2, wherein the exterior shell hasa thickness between or equal to 0.010 to 0.020 inches.
 4. The surgicalfastener of claim 3, wherein a combined transverse dimension of the coreand shell is between or equal to 0.018-0.035 inches.
 5. The surgicalfastener of claim 1, wherein the shell completely surrounds the core ofthe coil body.
 6. The surgical fastener of claim 1, wherein the shellcomprises the magnesium alloy and the core comprises the bioabsorbablepolymer.
 7. The surgical fastener of claim 1, wherein the shellcomprises the bioabsorbable polymer and the core comprises the magnesiumalloy.
 8. A surgical fastener deployment system in combination with thesurgical fastener of claim 1, wherein the surgical fastener deploymentsystem is configured to deploy the surgical fastener.
 9. A surgicalfastener comprising: a head; and a coil body attached to and extendingfrom the head, wherein the coil body includes a channel extending alongat least a portion of a length of the coil body.
 10. The surgicalfastener of claim 9, further comprising an opening formed in the head,wherein the channel of the coil body is accessible through the opening.11. The surgical fastener of claim 10, wherein the opening is on aproximal surface of the head.
 12. The surgical fastener of claim 9,wherein the channel of the coil body is an internal channel of the coilbody.
 13. The surgical fastener of claim 9, wherein the channel of thecoil body is an external channel.
 14. The surgical fastener of claim 9,wherein the channel extends along an entire length of the coil body. 15.The surgical fastener of claim 9, wherein the channel is constructed andarranged to receive a support at least partially disposed within thechannel when the surgical fastener is deployed from a fastenerdeployment device.
 16. A surgical fastener deployment system incombination with the surgical fastener of claim 15, wherein the surgicalfastener deployment system is configured to deploy the surgical fastenerand the surgical fastener deployment system includes the support,wherein the support is constructed and arranged to be positioned withinthe channel and support the surgical fastner during at least a portionof a deployment of the surgical fastener.
 17. A method of applying asurgical fastener comprising: inserting a support into a channel formedin and extending along at least a portion of a length of a coil body ofa coil fastener; deploying the surgical fastener while the support is atleast partially located in the channel.
 18. The method of claim 17,further comprising inserting the support into the channel through a holeformed in a head of the coil fastener.
 19. The method of claim 17,further comprising rotating the fastener as it is deployed.
 20. Themethod of claim 17, wherein the channel extends along an entire lengthof the coil body.
 21. The method of claim 17, further comprisingremoving the support from the channel as the surgical fastener isdeployed.
 22. The method of claim 17, further comprising removing thesupport from the channel after the surgical fastener is deployed.
 23. Asurgical fastener comprising: a head; and a coil body attached to anddistally extending from the head, wherein the coil body is composed of amagnesium alloy with a yield strength of between or equal to 314 MPa to506 MPa, and wherein a transverse dimension of a cross section of a coilwinding of the coil body is between or equal to 0.018-0.035 inches. 24.The surgical fastener of claim 23, wherein the magnesium alloy comprisesat least magnesium, dysprosium, neodymium and/or europium, and zincand/or zirconium.
 25. The surgical fastener of claim 23, wherein thehead is comprised of a bioabsorbable material.
 26. A surgical fastenerdeployment system in combination with the surgical fastener of claim 23,wherein the surgical fastener deployment system is configured to deploythe surgical fastener.
 27. A surgical fastener comprising: a head; and acoil body attached to and extending distally from the head, wherein thecoil body is comprised of a magnesium alloy that is 5.0%-25.5% by weightdysprosium, 0.01%-5% by weight neodymium and/or europium, 0.1%-3.0% byweight zinc, and 0.1%-2.0% by weight zirconium.
 28. The surgicalfastener of claim 27, wherein the head is comprised of a bioabsorbablematerial.
 29. The surgical fastener of claim 27, wherein a transversedimension of a cross section of a coil winding of the coil body isbetween or equal to 0.018-0.035 inches.
 30. A surgical fastenerdeployment system in combination with the surgical fastener of claim 27,wherein the surgical fastener deployment system is configured to deploythe surgical fastener.